Products based on wood fibers, or other fibers of lignocellulosic material, in which the fibers have been bonded together to form a comparatively homogeneous body have found extensive uses in the construction industry. The predominant product is sheets of such material, i.e. fiberboards (hard board, fiber building boards), of varying densities, although some manufacture of more complex products also takes place. It has previously been difficult and expensive to develop such fiber-based products that can be used in the presence of moisture. Fiberboards and other fiber-based products are, accordingly, used mostly indoors in dry environments. To date the means of reducing their sensitivity to moisture has been treatment with oil to make oil-tempered fiberboard, usually with high density. The treatment is expensive and only results in boards with some water-repellant properties. However, the board will not become dimensionally stabilized by such a treatment.